��runningServersForked should be read with runningServerReg held

The current code in `fork()` is racy in the sense that two concurrent go routines might call fork() at the same time, see that �runningServersForked is false and perform two forks. Holding runningServerReg makes sure that only one of the goroutines will see runningServersForked set to false.

Author: deweerdt

endless.go

@@ -416,12 +416,13 @@ func (srv *endlessServer) hammerTime(d time.Duration) {
 }
 
 func (srv *endlessServer) fork() (err error) {
+ runningServerReg.Lock()
+ defer runningServerReg.Unlock()
+ 
  // only one server isntance should fork!
  if runningServersForked {
  return errors.New("Another process already forked. Ignoring this one.")
 	}
- runningServerReg.Lock()
- defer runningServerReg.Unlock()
 
  runningServersForked = true